1 files changed, 10 insertions, 1 deletions
diff --git a/src/mongo/db/query/plan_enumerator.h b/src/mongo/db/query/plan_enumerator.h
index b82b738c57b..9eabd5b09b9 100644
--- a/src/mongo/db/query/plan_enumerator.h
+++ b/src/mongo/db/query/plan_enumerator.h
@@ -44,7 +44,8 @@ namespace mongo {
 struct PlanEnumeratorParams {
     PlanEnumeratorParams()
         : maxSolutionsPerOr(internalQueryEnumerationMaxOrSolutions.load()),
-          maxIntersectPerAnd(internalQueryEnumerationMaxIntersectPerAnd.load()) {}
+          maxIntersectPerAnd(internalQueryEnumerationMaxIntersectPerAnd.load()),
+          disableOrPushdown(disableMatchExpressionOptimization.shouldFail()) {}
 
     // Do we provide solutions that use more indices than the minimum required to provide
     // an indexed solution?
@@ -69,6 +70,11 @@ struct PlanEnumeratorParams {
     // all-pairs approach, we could wind up creating a lot of enumeration possibilities for
     // certain inputs.
     size_t maxIntersectPerAnd;
+
+    // Whether to disable OR-pushdown optimization. OR-pushdown assumes that the expression has been
+    // simplified: for example, that single-child $or nodes are unwrapped. To avoid this, when
+    // the 'disableMatchExpressionOptimization' failpoint is set, we also disable OR-pushdown.
+    bool disableOrPushdown;
 };
 
 /**
@@ -594,6 +600,9 @@ private:
 
     // How many things do we want from each AND?
     size_t _intersectLimit;
+
+    // Whether we should disable OR-pushdown optimization.
+    const bool _disableOrPushdown;
 };
 
 }  // namespace mongo